Multiple platforms --
-- as several other commentards mention, usually means multiple OSes. My wife is a Mac user, I uses Linux at home and must use Win 7 at work. Obviously Chrome and Firefox work across all my machines. Obviously neither IE nor Edge do so. With a bit o'tweaking I can get a consistent browser config whether I'm on the Ubuntu box, the wife's Mac Air, or the Windows box on my work desk.
Cloudy apps? Some of my machines are air-gapped. They can't see clouds. I run desktop applications. Of course the cloud can be useful for backups... unless someone fries them for you. (Netgear said sorry, so it's all good.) And unless the services are down (again). Lookin' at you, Microsoft.
Microsoft has a history of introducing powerful but insecure technology. Hypertext applications that run VBScript using IE's engine. Office macros, beloved by blackhats worldwide. Silverlight, ActiveX. Will the MS leopard change its security blind-spots with Edge?
Sometimes a browser should be just a browser.